1. Field of Invention
This invention relates to acoustical panels, and more particularly to panels usable in and around high speed gas flow areas of aircraft including but not restricted to inlet liners for jet and turbo-jet engines.
2. Description of the Prior Art
A preliminary search directed to the subject matter of this invention revealed Fisher, U.S. Pat. No. 2,087,248; Schenk, U.S. Pat. No. 2,140,210 and Gildard III, et al, U.S. Pat. No. 3,115,948. These patents generally disclose sound absorbant materials including some of the elements found in the present invention, but none of the patents singularly or taken in combination suggest the combination of constitutant elements presently disclosed and claimed which have been found to yield superior sound absorbing qualities, resistance to severe environment, and eliminates penetration of foreign matter into the acoustic material.
Other U.S. Patents of general interest which were found in the search as follows:
U.S. Pat. No. 1,721,461 Mazer, July 16, 1929;
U.S. Pat. No. 1,824,240 Smith, Sept. 22, 1931;
U.S. Pat. No. 3,021,914 Wilson, Feb. 20, 1962;
U.S. Pat. No. 3,439,774 Callaway, et al, Apr. 22, 1969;
U.S. Pat. No. 3,905,443 Sluezac, Sept. 16, 1975.